BMAL1 and major depressive disorder: In this study, we ablated BMAL1 in cynomolgus monkeys (Macaca fascicularis) and observed arrhythmic circadian activities in pre-adolescent monkeys, with altered rapid eye movement (REM) and non-REM (NREM) sleep, disrupted circadian cycling of many hormones, as well as behaviors resembling anxiety, depression and schizophrenia in humans.